Experts say balcony collapse that killed 6 likely due to dry rot

Officials order removal of 3rd-floor balcony

Experts say the balcony collapse that killed six people and seriously injured seven others early Tuesday morning, sending shockwaves across the Bay Area and Ireland, was likely due to dry rot.

On Tuesday evening, the city ordered the removal of the third-floor balcony below the one that collapsed at 2020 Kittredge St. after inspectors deemed it structurally unsafe, presenting a “collapse hazard endangering public safety.” Officials have prohibited access to the remaining two balconies in the building, and the property owner was mandated Tuesday to structurally assess them within 48 hours.

Of the collapse victims, many were Irish nationals. The seven injured people were sent to Highland Hospital in Oakland, Eden Medical Center in Castro Valley and John Muir Medical Center in Walnut Creek. The hospitals could not disclose Wednesday the conditions of the victims.

Although the city has not released the full results of the structural assessment, engineering experts have examined photos of the accidents.

The balcony, built with a timber structure, was susceptible to moisture and rainwater, said UC Berkeley civil and environmental engineering professor Abolhassan Astaneh-Asl, who visited the collapse site.

The balcony was built under 1998 city codes mandating that it hold 60 pounds per square foot, with a 1.5 safety factor — meaning it could potentially hold 90 pounds per square foot, according to Astaneh-asl. Under that code, he said, the balcony should have been able to withstand the weight of the 13 people who fell from it.

“(The balcony) could take these 13 people, but then because of the dry rot, the factor of safety is gone,” Astaneh-Asl said.

Ray Kirby, a consultant of the failure-analysis firm Childress Engineering Services, said state building codes increased the load requirements to 100 pounds per square foot for such apartment buildings in 2008, one year after construction was completed.

But an international building “model code” published in 2000 sets 100 pounds per square foot as the minimum design load, according to Kirby. Astaneh-Asl said most engineers use the 100-pounds-per-square-foot standard, even if state or city codes are lower.

“It’s a small area anyway — you wouldn’t (have to) spend too much money on it, but imagine the consequences,” Astaneh-Asl said.

The city hasn’t confirmed whether the collapsed balcony met only the minimum 60-pounds-per-square-foot standard or surpassed it. According to city spokesperson Matthai Chakko, the balcony was about 4 feet 6 inches by 8 feet 11 inches. If the balcony had met only the minimum weight requirements, a platform of those dimensions would have been able to hold about 2,400 pounds.

The building’s contractor was Segue Construction, Inc. and its architect was Thomas P. Cox Architects, Inc. Review of the building plans began in 2001, and construction was finalized roughly six years later.

Berkeley Rent Board public information unit manager Nick Traylor said the number of complaints sent to the rent board about this building is significant for a building that is not rent controlled, and thus not necessarily subject to as many rent-related complaints.

According to documents from the Berkeley Rent Board, complaints received by the building include reports of lights not being fixed, a fire escape door being jammed and excrement not being cleaned on the stairwell.

Although on the fourth residential floor, the failed balcony was on the building’s overall fifth floor.